Altera SerialLite II Protocol Bedienungsanleitung PDF herunterladen (Seite 43)

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SerialLite II Protocol Reference Manual

SerialLite II Specification

Figure 2–22. Packet Nesting Example

Packet Nesting Rules

The following packet nesting rules must be followed:

1. Nested packets must be started on lane number 0 of a new column.

2. Priority packets cannot be nested in other priority packets.

3. Data and priority packets must follow the packet interleaving rules

as defined in “Packet Interleaving Rules” on page 2–43.

Interleaved Data Packets

For applications that require bursting and nesting, SerialLite II allows the

the transmission of packets to be suspended and continued. Interleaving

is supported for both priority and data packets. The suspend user packet

(SUP) character interrupts the current packet and continuation of data

packet (CDP) and continuation of priority packet (CPP) identifies the

switch to a different channel address. For more information on channel

multiplexing see “Channel Multiplexing” on page 2–56.

There will be an impact on bandwidth efficiency as additional overhead

is associated with suspending and continuing packets. To minimize the

overhead impact, switch between packet channel numbers on large

bursts. Suspending and continuing to the same channel number is

allowed, but it consumes additional bandwidth. The suspension of a

priority packet must be done on the segment size boundary.

Packet Interleaving Rules

The following packet interleaving rules must be followed:

1. The suspend user packet sequence {SUP} must be transmitted on

lane number 0.

SLP Link Management

SPP Prioirity Payload EGP

SDP Data Payload EGP

SDP SPPSUP EGPEGP CDPSLP Link ManagementPr io r it y Pr io r it y DataData

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